Well, I am not sure what "solving over the domain" is, but moving x to the right and 42 to the left gives 7x = 42, from where x can be found.

Dec 2nd 2010, 11:02 AM

bdubb

Quote:

Originally Posted by emakarov

Well, I am not sure what "solving over the domain" is, but moving x to the right and 42 to the left gives 7x = 42, from where x can be found.

I still don't understand.:(

Dec 2nd 2010, 11:06 AM

Plato

Quote:

Originally Posted by bdubb

I still don't understand.:(

What is there not to understand?
You simply must tell in detail what difficulty you are having with problem.
Can you solve

Dec 2nd 2010, 11:13 AM

emakarov

If you have an equation a = b, you can add c to both sides to get a + c = b + c. This is just like if you have weighing scales that are balanced, you can put equal weight on both sides while preserving the balance. Similarly, you can subtract c from both sides of the equation a = b to get a - c = b - c.

To understand this, you need to know how to rearrange and simplify algebraic equations, such as adding like terms.

Edit: You can also substitute each of the numbers 0, 2, 4, 6 for x in the equation x = 8x - 42 and see which of them turns it into a true equality.

Dec 2nd 2010, 11:40 AM

Bacterius

I think he doesn't understand the "domain" part. Basically, it means you need to solve the equation within the subset given to you which here is a discrete set of integer values, namely . Typically, you would first solve the equation completely then discard any solution that doesn't fit within the subset, so let's try that :

is the solution and it is within the domain, thus is the solution to the question.

But that question is quite retarded in the sense that it doesn't properly show the concept of restricted domain ... because imagine the equation above had another integer solution (not true but it's an example) which was for instance . The number is not in the domain , therefore you need to discard it.

Does it make sense ?

Dec 2nd 2010, 11:43 AM

bdubb

Quote:

Originally Posted by Bacterius

I think he doesn't understand the "domain" part. Basically, it means you need to solve the equation within the subset given to you which here is a discrete set of integer values, namely . Typically, you would first solve the equation completely then discard any solution that doesn't fit within the subset, so let's try that :

Yes now i understand! thanks!!

is the solution and it is within the domain, thus is the solution to the question.

But that question is quite retarded in the sense that it doesn't properly show the concept of restricted domain ... because imagine the equation above had another integer solution (not true but it's an example) which was for instance . The number is not in the domain , therefore you need to discard it.

Does it make sense ?

Yes, so it would be 6

Dec 2nd 2010, 11:47 AM

Bacterius

But it wouldn't be , or , or , if these solutions came up, that's what's important to understand in this question. Only solutions to the equation that are within the set are solutions to the actual question. Any other number needs to be discarded.